486
FXUS02 KWBC 241959
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
359 PM EDT SUN MAY 24 2026
VALID 12Z WED MAY 27 2026 - 12Z SUN MAY 31 2026
...HEAVY RAIN AND THUNDERSTORMS EXPECTED TO CONTINUE ACROSS MUCH
OF THE SOUTHERN U.S...
..OVERVIEW
MULTIPLE PIECES OF ENERGY WITHIN A SOUTHERN STREAM SHORTWAVE WILL
PASS THROUGH THE SOUTH-CENTRAL U.S. DURING THE WEEK, PROVIDING LIFT
FOR WIDESPREAD RAIN AND THUNDERSTORMS IN A MOIST AND UNSTABLE
ENVIRONMENT STRETCHING THROUGH THE SOUTHEAST AS WELL. HEAVY RAIN IS
LIKELY TO FOCUS IN TEXAS AND THE LOWER MISSISSIPPI VALLEY MIDWEEK,
POTENTIALLY OVER AREAS THAT WILL ALREADY HAVE WET ANTECEDENT
CONDITIONS, LEADING TO FLOODING CONCERNS. OUT WEST, A CLOSED UPPER
LOW SHOULD BE ATOP THE GREAT BASIN MID TO LATE WEEK, RESULTING IN
COOLER TEMPERATURES AND PRECIPITATION FOR THE WEST AS IT MEANDERS
WHILE WEAKENING. A BLOCKY UPPER RIDGE IS SET TO STRETCH ACROSS THE
NORTH-CENTRAL U.S. AND BRING ABOVE AVERAGE TEMPERATURES THROUGH
MUCH OF THE PERIOD. MEANWHILE A COUPLE OF UPPER TROUGHS/LOWS SHOULD
PUSH THROUGH THE NORTHEAST AND ALLOW FOR PRECIPITATION CHANCES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
MODEL GUIDANCE IS AGREEABLE IN SHOWING AN UPPER LOW CENTERED OVER
THE CENTRAL GREAT BASIN THROUGH LATE WEEK. THE LOW IS FORECAST TO
GRADUALLY WEAKEN AND TRACK NORTHEAST FRIDAY INTO NEXT WEEKEND WHILE
JOINING WITH A NORTHEASTERN PACIFIC TROUGH. TO THE EAST, UPPER
RIDGING WILL STRETCH FROM THE SOUTHEAST NORTHWESTWARD INTO THE
MIDWEST AS SOUTHERN STREAM ENERGY CUTS INTO IT IN THE SOUTH-CENTRAL
U.S., WITH TYPICAL MODEL DIFFERENCES IN THE DETAILS. AS THE
SOUTHERN ENERGY WEAKENS AND MOVES EAST, THE RIDGE LOOKS TO REFORM
WITH A NEUTRAL TILT ACROSS THE PLAINS LATE WEEK INTO THE WEEKEND.
THE PATTERN STARTS TO LOOK MORE LIKE AN OMEGA BLOCK AS TROUGHING
RETROGRADES INTO THE NORTHEAST. THERE CONTINUES TO BE QUITE A BIT
OF UNCERTAINTY WITH THE NORTHEAST TROUGH, WITH THE COMPLICATING
FACTOR OF LIKELY TWO DIFFERENT VORT MAXES MOVING THROUGH. GFS AND
AI-GFS RUNS ARE ON THE FASTER SIDE WITH BOTH, WITH THE NON-NCEP
GUIDANCE SLOWER.
THE WPC FORECAST WAS BASED ON A MULTI-MODEL BLEND EARLY IN THE
FORECAST PERIOD, WITH INCREASING PROPORTIONS OF THE ENSEMBLE MEANS
TO ABOUT HALF BY THE END OF THE PERIOD TO MITIGATE THE INDIVIDUAL
MODEL DIFFERENCES.
..WEATHER/HAZARDS HIGHLIGHTS
PERSISTENT SOUTHERN STREAM ENERGY WILL CONTINUE TO KEEP MUCH OF
THE SOUTHERN PLAINS TO THE SOUTHEAST ACTIVE AND UNSETTLED WELL INTO
NEXT WEEK WITHIN A VERY MOIST AND UNSTABLE ENVIRONMENT AND DAILY
THUNDERSTORM CHANCES. THIS COULD BE ESPECIALLY IMPACTFUL FOR PARTS
OF TEXAS AND THE LOWER MISSISSIPPI VALLEY WHERE RECENT RAINS AND
ADDITIONAL RAIN IN THE SHORT TERM HAS LEAD TO RATHER SATURATED
GROUNDS. FOR THE DAY 4/WEDNESDAY ERO, A BROAD MARGINAL RISK IS IN
PLACE ACROSS MUCH OF THE SOUTHERN U.S., AND CONTINUE TO HIGHLIGHT
AN EMBEDDED SLIGHT RISK FOR SOUTHEAST TEXAS TO WESTERN LOUISIANA. A
BROAD MARGINAL RISK IS IN PLACE ON THE DAY 5/THURSDAY ERO FOR THE
LOWER AND MIDDLE MISSISSIPPI VALLEY BACK INTO THE CENTRAL PLAINS.
AN UPGRADE TO A SLIGHT RISK FOR PARTS OF THE CENTRAL GULF COAST IS
NOT OUT OF THE QUESTION, DEPENDING ON PREVIOUS DAYS' RAINFALL, BUT
UNCERTAINTIES IN THE POSITION OF HEAVY RAIN (INCLUDING THE
POTENTIAL FOR MAX AMOUNTS TO BE OFFSHORE) PRECLUDE AN UPGRADE FOR
NOW. THE EXACT LOCATIONS OF HEAVIER RAINFALL ON BOTH DAYS WILL
LIKELY CHANGE AS MODELS COME INTO BETTER AGREEMENT, BUT THE PATTERN
OVERALL FAVORS HEAVY RAINFALL POTENTIAL WITH FLOODING STILL A
CONCERN GIVEN THE POTENTIALLY CONCERNING ANTECEDENT CONDITIONS. THE
PATTERN EVOLUTION MAY GRADUALLY SUPPORT DRIER CONDITIONS FOR TEXAS
BY NEXT WEEKEND, BUT THE WET PATTERN LOOKS TO CONTINUE ALONG THE
GULF COAST AND ESPECIALLY FLORIDA THROUGH NEXT WEEKEND. A MARGINAL
RISK REMAINS IN PLACE FOR THE URBAN CORRIDOR OF SOUTHEAST FLORIDA
ON THURSDAY, WITH HEAVY RAINFALL POTENTIAL TRENDING UPWARDS BEYOND
AS WELL.
UPPER TROUGHING ACROSS THE NORTHWEST AND MEANDERING AROUND THE
GREAT BASIN WITH A FRONTAL SYSTEM AHEAD OF IT WILL ALLOW FOR
INCREASED PRECIPITATION ACROSS THE PACIFIC NORTHWEST TO
INTERMOUNTAIN WEST FOR MULTIPLE DAYS. SNOW IS POSSIBLE ACROSS
HIGHER ELEVATIONS, WITH HIGHEST AMOUNTS NOW MOST LIKELY IN THE
SIERRA NEVADA. COMBINING ENERGIES WILL ALLOW RAIN CHANCES TO
STRETCH EAST INTO THE CENTRAL PLAINS AND MIDWEST FOR MIDWEEK AND
BEYOND.
WITH THE CLOSED UPPER LOW OVER THE WEST, TEMPERATURES SHOULD TREND
COOLER IN THIS REGION THROUGH THURSDAY, WITH SOME MODERATING BACK
TOWARDS NORMAL AS THE TROUGH WEAKENS AND DRIFTS. THE UPPER RIDGE TO
ITS EAST WILL ALLOW FOR WARMER THAN AVERAGE TEMPERATURES ACROSS
THE NORTH-CENTRAL U.S. THROUGH MUCH OF NEXT WEEK, WITH DAYTIME
HIGHS 10-20 DEGREES ABOVE NORMAL, WITH GREATEST ANOMALIES THROUGH
AROUND MID TO LATE WEEK.
TATE/SANTORELLI
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION FORECAST, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY MESSAGES
ARE AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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